Core 4, the immunology/pathology core, provides services to all eight projects. It offers histologic support, qualitative pathologic interpretation and quantitative morphometric assessment of human and animal lung material supervised by a pulmonary pathologist. A large variety of immunological assessments are also offered. Class-specific immunoglobulin and antigen-specific antibody levels are available for human and rabbit sera and other fluids, with a special emphasis on IgE antibodies. The core also provides expertise in immunization of rabbits for preferentially inducing IgE antibodies. Histamine can be assayed by the radioenzymatic technique. Lymphocyte- related immunological assays include antigen- and mitogen- induced blast transformation, production of interleukin 2 and interferon, quantitation of Appropriate networks are in place to accomplish simultaneous analyses of these cells in each sample. Cost savings derive from the same people performing assays or histologic assessments for different projects and the capability of batching samples in antibody assays. Even more importantly, these measures provide uniformity in the data variance attributable to technique and thus results from different (current as well as proposed) projects can be directly compared.